This invention relates to a carton, particularly for packaging liquids and a blank therefor. The carton is made of a cardboard sheet bilaterally coated with a heat-sealable synthetic material and has a sealed pouring aperture which is opened by the consumer by breaking (tearing) the seal. the blank has panels separated from one another by fold lines. The panels comprise a first wide panel flanked by two narrow side panels. Each side panel is adjoined by a half panel which, when the carton is formed, are connected to one another by a longitudinal seam to form a second wide panel. All these panels together form a panel field adjoined at the top and bottom by a flap field for forming, by a central transversal seam, a gable portion which can be folded flat.
In cartons for liquids, problems involving the formation and operation of pouring apertures are well known. The apertures should be closed airtight when the carton is marketed, and they should be easily openable to ensure that children, aged and frail persons may open the package without the need to resort to any implement. The pouring aperture should have or should be brought into such a shape which ensures air admission to make possible an even outflow of the contents. Further, the pouring aperture should be at a location which makes possible a filling of the carton with little or no air admission, because the presence of air in the carton leads to an accelerated spoiling of the contents and also represents an unused space resulting in the need for additional material having added unnecessary expense.
A carton having a rectangular base may be formed from a blank consisting of a wide panel, flanked on both sides by narrow panels which, in turn, are adjoined by two half panels for forming the other wide panel when connected with a longitudinal seam. On each side of the wall panels flap portions are provided for the bilateral closing of the bottom and top wall by means of a transverse waLl so that a folded construction is obtained. On either side of the narrow panels triangular fold lines are provided by means of which triangular ears are formed. In some carton constructions the triangular ear is provided with a pouring aperture, in others the ear can be torn or slit open by scissors. In cartons having a square base the side walls are of identical size.
The advantage of placing the pouring aperture in the triangular ear resides particularly in the fact that the carton may be practically entirely filled since the triangular ear has to be lifted for opening and therefore is situated above the level of the liquid contents.
An arrangement of the above-outlined type is disclosed in German Auslegeschrift (published examined application) 1,486,682. On the inside of the foldable triangular ear there is situated a tear-open pouring aperture which is covered by an additional strip. The latter projects beyond the triangular ear and therefore may be easily grasped. It is a disadvantage of this arrangement that additional manufacturing steps are needed for the positioning and gluing of the strip which leads to added expense in making the carton.
A similar solution is proposed in German Offenlegungsschrift No. (non-examined published application) 2,407,175, according to which a covering strip also seals a second, smaller aperture in the top wall to ensure an unimpeded air intake during use.
German Offenlegungsschrift No. 2,939,093 discloses the provision of a cutting line in one wall of the overlapping parts of the narrow side wall and the triangular ear and to connect the walls with a closely adjoining, very narrow welded seam in a liquidtight manner. The seam, however, should be of the type which can be torn open easily to expose the opening. Such a particular seal has to be provided in a very accurate manner to ensure a liquidtight closure.